RESUMO
We analyzed circulation time (rABCT) and vascular volume density images obtained by angio-computerized tomography (angio-CT) in 63 patients with small deep cerebral infarctions. Abnormalities in the rABCT image were found in 88% of the patients and in the vascular volume image in 48%. Two groups with different clinical pictures were picked out by rABCT changes: one with major-vessel involvement, the other with small-vessel involvement. The perfusional changes found were mainly due to altered vascular canalization rather than to altered vasomotility. The hemodynamic theory could explain the spatial relations between perfusion changes and CT hypodense areas without needing assumptions linking blood flow and metabolism.
Assuntos
Angiografia Cerebral , Infarto Cerebral/diagnóstico por imagem , Circulação Cerebrovascular , Tomografia Computadorizada por Raios X , Viscosidade Sanguínea , Volume Sanguíneo , Barreira Hematoencefálica , Encéfalo/irrigação sanguínea , Encéfalo/metabolismo , Artérias Cerebrais/patologia , Artérias Cerebrais/fisiopatologia , Infarto Cerebral/patologia , Infarto Cerebral/fisiopatologia , Circulação Colateral , Meios de Contraste/farmacocinética , Hemodinâmica , Humanos , Intensificação de Imagem Radiográfica , Fatores de Tempo , Sistema Vasomotor/fisiopatologiaRESUMO
We performed rapid sequential computerized tomography (CT) scanning following i.v. injection of a bolus of contrast medium, and generated three functional images related, respectively, to intravascular circulation time (rABCT), vascular volume density (Vv) and blood-brain barrier (BBB) unidirectional constant uptake rate (Ki). This was accomplished by calculating the first mathematical moment of the monitored time-density curves about the injection time, and by the multiple time graph analysis described by Patlack and coworkers. A satisfactory resolution was achieved, allowing separate appreciation of changes in rABCT both at large vessels and at tissue small vessels. Combined evaluation of rABCT and Vv images allowed us to draw qualitative conclusions about blood flow and perfusion reserve.